The authors would like to acknowledge Marc Ferrer at the National Center for Advancing Translational Sciences, National Institutes of Health for his support and guidance on the initial development of these assays. In addition, we would like to thank Alyson Freeman, Mariela Jaskelioff, Michael Acker, Jacob Haling, and Vesselina Cooke for their scientific input and discussion as project team members.

1. Culturing of 1536-well 3D Tumor Spheroids
<ol>
	<li>Prepare a fresh 3D tumor spheroid medium stem (cell medium + knockout serum replacement + insulin-transferrin-selenium) by adding the following reagents to 500 mL of Dulbecco&#39;s Modified Eagles Medium (DMEM/F12): 1x penicillin/streptomycin, 10 ng/mL of human basic fibroblast growth factor (bFGF), 20 ng/mL of human epidermal growth factor (EGF), 0.4% bovine serum albumin (BSA) (Fraction V), 1x insulin-transferrin-selenium, and 1% knockout (KO) serum replacement (...

<ol>
	<li>Lee, M., Vasioukhin, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cell+polarity+and+cancer--cell+and+tissue+polarity+as+a+non-canonical+tumor+suppressor.">Cell polarity and cancer--cell and tissue polarity as a non-canonical tumor suppressor.</a> Journal of Cell Science. 121 (Pt 8), 1141-1150 (2008).</li><li>Nath, S., Devi, G. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+culture+systems+in+cancer+research:+Focus+on+tumor+spheroid+model.">Three-dimensional culture systems in cancer research: Focus on tumor spheroid model.</a> Pharmacology &amp; Therapeutics. 163, 94-108 (2016).</li><li>Weigelt, B., Ghajar, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+need+for+complex+3D+culture+models+to+unravel+novel+pathways+and+identify+accurate+biomarkers+in+breast+cancer.">The need for complex 3D culture models to unravel novel pathways and identify accurate biomarkers in breast cancer.</a> Advanced Drug Delivery Reviews. 69, 42-51 (2014).</li><li>Li, Q., Chow, A. B., Mattingly, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-dimensional+overlay+culture+models+of+human+breast+cancer+reveal+a+critical+sensitivity+to+mitogen-activated+protein+kinase+kinase+inhibitors.">Three-dimensional overlay culture models of human breast cancer reveal a critical sensitivity to mitogen-activated protein kinase kinase inhibitors.</a> The Journal of Pharmacology and Experimental Therapeutics. 332 (3), 821-828 (2010).</li><li>Li, L., Lu, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimizing+a+3D+Culture+System+to+Study+the+Interaction+between+Epithelial+Breast+Cancer+and+Its+Surrounding+Fibroblasts.">Optimizing a 3D Culture System to Study the Interaction between Epithelial Breast Cancer and Its Surrounding Fibroblasts.</a> Journal of Cancer. 2, 458-466 (2011).</li><li>Pickl, M., Ries, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+3D+and+2D+tumor+models+reveals+enhanced+HER2+activation+in+3D+associated+with+an+increased+response+to+trastuzumab.">Comparison of 3D and 2D tumor models reveals enhanced HER2 activation in 3D associated with an increased response to trastuzumab.</a> Oncogene. 28 (3), 461-468 (2009).</li><li>Nyga, A., Cheema, U., Loizidou, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+tumour+models:+novel+in+vitro+approaches+to+cancer+studies.">3D tumour models: novel in vitro approaches to cancer studies.</a> Journal of Cell Communication and Signaling. 5 (3), 239-248 (2011).</li><li>Kimlin, L. C., Casagrande, G., Virador, V. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+three-dimensional+(3D)+models+in+cancer+research:+an+update.">In vitro three-dimensional (3D) models in cancer research: an update.</a> Molecular Carcinogenesis. 52 (3), 167-182 (2013).</li><li>Mathews Griner, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Large-scale+pharmacological+profiling+of+3D+tumor+models+of+cancer+cells.">Large-scale pharmacological profiling of 3D tumor models of cancer cells.</a> Cell Death &amp; Disease. 7 (12), e2492 (2016).</li><li>Polo, M. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Responsiveness+to+PI3K+and+MEK+inhibitors+in+breast+cancer.+Use+of+a+3D+culture+system+to+study+pathways+related+to+hormone+independence+in+mice.">Responsiveness to PI3K and MEK inhibitors in breast cancer. Use of a 3D culture system to study pathways related to hormone independence in mice.</a> PLoS One. 5 (5), e10786 (2010).</li><li>Hatzivassiliou, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RAF+inhibitors+prime+wild-type+RAF+to+activate+the+MAPK+pathway+and+enhance+growth.">RAF inhibitors prime wild-type RAF to activate the MAPK pathway and enhance growth.</a> Nature. 464 (7287), 431-435 (2010).</li><li>Bhargava, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Registered+report:+RAF+inhibitors+prime+wild-type+RAF+to+activate+the+MAPK+pathway+and+enhance+growth.">Registered report: RAF inhibitors prime wild-type RAF to activate the MAPK pathway and enhance growth.</a> Elife. 5, e09976 (2016).</li><li>Mathews, L. A., Hurt, E. M., Zhang, X., Farrar, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epigenetic+regulation+of+CpG+promoter+methylation+in+invasive+prostate+cancer+cells.">Epigenetic regulation of CpG promoter methylation in invasive prostate cancer cells.</a> Molecular Cancer. 9, 267 (2010).</li><li>Mathews, L. A., Crea, F., Farrar, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epigenetic+gene+regulation+in+stem+cells+and+correlation+to+cancer.">Epigenetic gene regulation in stem cells and correlation to cancer.</a> Differentiation. 78 (1), 1-17 (2009).</li><li>Mathews, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+expression+of+DNA+repair+genes+in+invasive+human+pancreatic+cancer+cells.">Increased expression of DNA repair genes in invasive human pancreatic cancer cells.</a> Pancreas. 40 (5), 730-739 (2011).</li><li>Mathews, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+1536-well+quantitative+high-throughput+screen+to+identify+compounds+targeting+cancer+stem+cells.">A 1536-well quantitative high-throughput screen to identify compounds targeting cancer stem cells.</a> Journal of Biomolecular Screening. 17 (9), 1231-1242 (2012).</li><li>Horii, T., Nagao, Y., Tokunaga, T., Imai, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serum-free+culture+of+murine+primordial+germ+cells+and+embryonic+germ+cells.">Serum-free culture of murine primordial germ cells and embryonic germ cells.</a> Theriogenology. 59 (5-6), 1257-1264 (2003).</li><li>Sun, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Epigenetic+regulation+of+SOX9+by+the+NF-kappaB+signaling+pathway+in+pancreatic+cancer+stem+cells.">Epigenetic regulation of SOX9 by the NF-kappaB signaling pathway in pancreatic cancer stem cells.</a> Stem Cells. 31 (8), 1454-1466 (2013).</li><li>Mathews, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+1536-well+quantitative+high-throughput+screen+to+identify+compounds+targeting+cancer+stem+cells.">A 1536-well quantitative high-throughput screen to identify compounds targeting cancer stem cells.</a> Journal of Biomolecular Screening. 17 (9), 1231-1242 (2012).</li><li>Mathews Griner, L. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-throughput+combinatorial+screening+identifies+drugs+that+cooperate+with+ibrutinib+to+kill+activated+B-cell-like+diffuse+large+B-cell+lymphoma+cells.">High-throughput combinatorial screening identifies drugs that cooperate with ibrutinib to kill activated B-cell-like diffuse large B-cell lymphoma cells.</a> Proceedings of the National Academy of Sciences of the United States of America. 111 (6), 2349-2354 (2014).</li><li>Herter, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+three-dimensional+heterotypic+spheroid+model+for+the+assessment+of+the+activity+of+cancer+immunotherapy+agents.">A novel three-dimensional heterotypic spheroid model for the assessment of the activity of cancer immunotherapy agents.</a> Cancer Immunology, Immunotherapy. 66 (1), 129-140 (2017).</li></ol>

The methods presented here demonstrate a detailed protocol on how to produce tumor spheroids in 1536-well plates for large-scale compound screenings. These methods were initially adapted from work at the National Cancer Institute where tumor spheroids were grown in low- throughput assays in 6-well and 96-well plates to ask questions about genetic dependencies and compound sensitivity13,14,15. A critical and unique feature of thi...

In the past decade, more and more studies have implemented the use of 3D cell culture models to understand concepts that are not fully recapitulated by growing cells in 2D on plastic. Examples of these concepts include the alternations in normal epithelial cell polarity1 where the spatial orientation of apical and basal layers of cells are lost, as well as the role of the extracellular matrix in regulating survival and cell fate. Oncology research, in particular, has used 3D models to understand the basic biology of cancer cells and the differences between 2D and 3D cell culture systems3,4. The development of more sophisticated cell culture techniques and their further adaption to multi-well formats has enabled the search for new drugs in 3D settings. In contrast to cells grown under 2D conditions, 3D models of tumors range in complexity from layered cellular systems5 to single-cell-type spheres of different sizes, to complex multi-cell-type spheres6,7,8. The discovery of novel compounds or biologics that potently induce cell death in these 3D model systems is, therefore, of high interest in drug development campaigns. Endpoints of these assays are often identical to those performed in 2D cultures to assess changes in cell proliferation, but when conducted in a more physiologically relevant setting, they may reveal the true level of dependency of the target gene or pathway being interrogated.
As introduced above, a variety of model systems have been developed to study drug responses in 3D culture systems, but the majority use either 96 or 384-well microtiter plates and are not easily adaptable to the high-throughput screening (HTS) formats often used in drug discovery screening campaigns. Such systems include the use of hanging droplet technologies, spheroid cultures, pulsating cells with magnetic particles to induce levitation, and cultures incorporating natural or synthetic gels such as collagen, Matrigel, or polyethylene glycol (PEG)2. Here, we present the detailed methods of a previously developed technique to produce 3D spheroid cultures from established cancer cell lines in a 1536-well plate format. In this protocol, a highly defined medium is used which prevents the attachment of normally adherent cell lines9. This system has limitations (i.e., it cannot fully recapitulate a complex model system of cancer), but nevertheless, these assays enable a high-throughput screening of large collections of small molecules and crosswise comparisons of drug response between 2D and 3D cultures against a variety of cell lines and compounds.
The cell lines selected to demonstrate the methods in this article all harbor mutations in genes related to the MAPK signaling pathway, a pathway which is highly dysregulated in cancer, and for which many therapeutics are available. Many of the lines have activating oncogenic mutations in the Kirsten Rat Sarcoma virus also referred to as KRAS, the Neuroblastoma RAS or NRAS, the Harvey Rat Sarcoma virus oncogene or HRAS, and the associated kinases Rapidly Accelerated Fibrosarcomas, also known as RAFs. Recent literature suggests that the inhibitors of different nodes of this pathway are uniquely more efficacious in a subset of the cell lines when grown under 3D conditions9,10. One study found that when cancer cells with active RAS were cultured in 3D, they demonstrated an increased sensitivity to MAPK inhibitors, and further, that this approach could identify pathways and targeted inhibitors that might be missed in the traditional 2D setting. The goal of this study is to present the methods used to culture these cell lines, and further, to demonstrate the differential responses to these inhibitors which can be observed only when using 3D cell culture systems.

<table>
	<tbody>
		<tr>
			<td>Reagents</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>DMEM Dulbecco`s Modified Eagle Media (DMEM)/F12</td>
			<td>ATCC</td>
			<td>30-2006</td>
			<td>Purchased as a prepared solution. This reciepe was found to be preferred compared to other vendors.</td>
		</tr>
		<tr>
			<td>DMEM Dulbecco`s Modified Eagle Media (DMEM)/F12</td>
			<td>Lonza</td>
			<td>12-604F</td>
			<td>Purchased as a prepared solution.</td>
		</tr>
		<tr>
			<td>Roswell Park Memorial Institute (RPMI)</td>
			<td>Lonza</td>
			<td>12-115Q</td>
			<td>Purchased as a prepared solution.</td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Seradigm</td>
			<td>1500-500</td>
			<td>Purchased as a prepared solution.</td>
		</tr>
		<tr>
			<td>1x 0.25% Trypsin with Ethylenediaminetetraacetic acid (EDTA)</td>
			<td>Hyclone</td>
			<td>SH30042.01</td>
			<td>Purchased as a prepared solution.</td>
		</tr>
		<tr>
			<td>1x Penicillin/Streptomycin</td>
			<td>Gibco</td>
			<td>15140</td>
			<td>Purchased as a prepared solution.</td>
		</tr>
		<tr>
			<td>10 ng/mL Human basic Fibrobast Growth Factor (bFGF)</td>
			<td>Sigma</td>
			<td>F0291</td>
			<td>Resuspend in sterile water.</td>
		</tr>
		<tr>
			<td>20 ng/mL Human Epidermal Growth Factor (EGF)</td>
			<td>Sigma</td>
			<td>E9644</td>
			<td>Resuspend in sterile water.</td>
		</tr>
		<tr>
			<td>0.4% Bovine Serum Albumin (BSA)</td>
			<td>Sigma</td>
			<td>A9418</td>
			<td>Resuspend in sterile PBS and filter.</td>
		</tr>
		<tr>
			<td>1x Insulin Transferrin Selenium (ITS)</td>
			<td>Gibco</td>
			<td>51500056</td>
			<td></td>
		</tr>
		<tr>
			<td>1% KnockOut (KO) Serum Replacement</td>
			<td>Gibco</td>
			<td>10828-028</td>
			<td>Add fresh right before use.</td>
		</tr>
		<tr>
			<td>100% Dimethyl sulfoxide (DMSO)</td>
			<td>Sigma</td>
			<td>276855-100ML</td>
			<td></td>
		</tr>
		<tr>
			<td>CellTiter-Glo</td>
			<td>Promega</td>
			<td>G7573</td>
			<td>Purchased as a prepared solution.</td>
		</tr>
		<tr>
			<td>Consumables</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Small Combi Cassette</td>
			<td>ThermoFisher</td>
			<td>24073295</td>
			<td></td>
		</tr>
		<tr>
			<td>Small Multiflow Cassette</td>
			<td>BioTek</td>
			<td>294085</td>
			<td></td>
		</tr>
		<tr>
			<td>1536-well sterile TC plates (white)</td>
			<td>Corning</td>
			<td>3727</td>
			<td></td>
		</tr>
		<tr>
			<td>1536-well sterile TC plates (black)</td>
			<td>Corning</td>
			<td>3893</td>
			<td></td>
		</tr>
		<tr>
			<td>Scivax Plates</td>
			<td>MBL International</td>
			<td>NCP-LH384-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Equipment</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Adhesives seals</td>
			<td>ThermoFisher</td>
			<td>AB0718</td>
			<td></td>
		</tr>
		<tr>
			<td>Spinning Incubator</td>
			<td>LiCONiC</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless Steel Lids</td>
			<td>The Genomics Institute of Novartis Research Foundation (GNF)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>ATS Acoustic Dispensor</td>
			<td>EDS Biosystems</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Echo Acoustic Dispensor</td>
			<td>Labcyte</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Luminometer</td>
			<td>Envision-Perkin Elmer</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Peristaltic Pump- Multidrop Combi</td>
			<td>ThermoFisher</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid Handler-Multiflow FX</td>
			<td>BioTek</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

generation of high-throughput three-dimensional tumor spheroids for drug screening

Cancer cells have routinely been cultured in two dimensions (2D) on a plastic surface. This technique, however, lacks the true environment a tumor mass is exposed to in vivo. Solid tumors grow not as a sheet attached to plastic, but instead as a collection of clonal cells in a three-dimensional (3D) space interacting with their neighbors, and with distinct spatial properties such as the disruption of normal cellular polarity. These interactions cause 3D-cultured cells to acquire morphological and cellular characteristics which are more relevant to in vivo tumors. Additionally, a tumor mass is in direct contact with other cell types such as stromal and immune cells, as well as the extracellular matrix from all other cell types. The matrix deposited is comprised of macromolecules such as collagen and fibronectin.
In an attempt to increase the translation of research findings in oncology from bench to bedside, many groups have started to investigate the use of 3D model systems in their drug development strategies. These systems are thought to be more physiologically relevant because they attempt to recapitulate the complex and heterogeneous environment of a tumor. These systems, however, can be quite complex, and, although amenable to growth in 96-well formats, and some now even in 384, they offer few choices for large-scale growth and screening. This observed gap has led to the development of the methods described here in detail to culture tumor spheroids in a high-throughput capacity in 1536-well plates. These methods represent a compromise to the highly complex matrix-based systems, which are difficult to screen, and conventional 2D assays. A variety of cancer cell lines harboring different genetic mutations are successfully screened, examining compound efficacy by using a curated library of compounds targeting the Mitogen-Activated Protein Kinase or MAPK pathway. The spheroid culture responses are then compared to the response of cells grown in 2D, and differential activities are reported. These methods provide a unique protocol for testing compound activity in a high-throughput 3D setting.

A variety of established cancer cell lines known to grow well under 2D culture conditions were tested using the methods outlined here. Representative images from a variety of MAPK mutant cancer cell lines (Calu-6:KRAS, NCI-H1299:NRAS, SK-MEL-30:NRAS, and KNS-62:HRAS) are seen in Figure 1. These images demonstrate that although the cell lines have various morphologies, each formed 3D structures in the 1536-well assay plates. Figure 2</stro...

Watch this Scientific Journal Video about Generation of High-Throughput Three-Dimensional Tumor Spheroids for Drug Screening at JoVE.com

Generation of High-Throughput Three-Dimensional Tumor Spheroids for Drug Screening

Across a wide variety of disease indications, more physiologically relevant models are being developed and implemented into drug discovery programs. The new model system described here demonstrates how three-dimensional tumor spheroids can be cultured and screened in a high-throughput 1536-well plate-based system to search for new oncology drugs.

Cancer cells have routinely been cultured in two dimensions (2D) on a plastic surface. This technique, however, lacks the true environment a tumor mass is ...

This method can help answer key questions in the drug discovery field, such as, what is the most relevant tissue culture setting for hit to lead identification. The main advantage of this technique is that it allows the culturing of cells in three dimensions, in a high throughput manner, using 1536 well-plates. Demonstrating this protocol will be Kalyani Gampa, a senior scientist from my lab.To set up a 3D tumor spheroid culture, detach the cancer cell lines of interest with three washes of BBS. Followed by the addition of one milliliter of trypsin per five centimeters squared area of culture flask. After five minutes, neutralize the trypsin with five times the volume of serum supplemented medium in each flask, and count the cells.Use a sterilized, small stainless steel tipped cassette with a peristaltic pump-based system to seed a total of 500 cells in eight microliters of spheroid medium into each well of a 1, 536 well tissue culture treated plate. Then use a breathable adhesive plate seal to cover the plate. And place the plate in a spinning incubator set at 37 degrees Celsius and 10rpm with 5%carbon dioxide and 95%relative humidity for three days.The single most critical step is ensuring that the plates are well sealed before they are placed into the incubator. The spheroids will need three days to form and this step prevents medium evaporation. At the end of the incubation, quick spin the cancer lined culture plates at 100 times gravity to collect any condensation, and remove the adhesive seals.Put each plate to be treated onto an acoustic dispenser set up to deliver a total of eight nanoliters of each compound. Dilution to a final concentration of 0.1%DMSO per well, and a top compound dose of 10 micromolar. When the compound has been added to the appropriate plates, place a custom made, stainless steel cell culture lid on to each plate to prevent evaporation, and return the plates to the spinning incubator for another five days.At the end of the incubation, add three microliters of pre-warmed cell lysis reagent, supplemented with luciferin to each well of each cell culture plate. And incubate the plates at room temperature for at least 15 minutes. Then capture the ATP luminesce on a plate luminometer.When all of the plates have been analyzed, extract the raw data from the instrument and normalize all of the fields containing the test compounds to the average of all the wells containing DMSO alone as the neutral control. The percent growth inhibition of each compound can then be calculated according to the formula, and dose response curves, and inhibitory IC50s can be generated. A variety of established cancer cells known to grow well under 2D culture conditions also formed 3D structures when cultured as just demonstrated, despite their morphological differences.When used for large scale screening, differential compound sensitivity between cultures grown in 2D versus those grown in 3D can be observed. With each dot representing the inhibitory concentration of a single compound for which a 50%cell killing response is observed in both culture settings. In this representative experiment, both tested RAF kinase inhibitory compounds were more potent in 3D conditions in a non-small cell lung cancer line culture harboring an activating mutation in the KRAS protein.However, the compounds demonstrate a similar potency in both 3D spheroid and 2D colon cancer line cultures that contain a G13D activating mutation in KRAS. The 3D assay also permits observation of the paradoxical growth activation phenomenon, which occurs when there is an incomplete inhibition of RAF dimers in highly activated RAFs mutant lines, as evidenced by cell growth at low concentrations of the drug, that is repressed at high concentrations. After its development, this technique paved the way for researchers in the field of cancer drug discovery to explore alternative culture conditions for identifying new, efficacious chemical matter against known targets.

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Cancer Research

8.4K ビュー.  Novartis Institutes for Biomedical Research. This method can help answer key questions in the drug discovery field, such as, what is the most relevant tissue culture setting for hit to lead identification. The main advantage of this technique is that it allows the culturing of cells in three dimensions, in a high throughput manner, using 1536 well-plates. Demonstrating this protocol will be Kalyani Gampa, a senior scientist from my lab.To set up a 3D tumor spheroid culture, detach the cancer cell lines of interest with three wash...